What do you mean, when you say you cannot open SEP Client Icon? From the Taskbar?
Have you tried launching directly from the [INSTALL DIRECTORY]\
SYMCORPUI.EXE ?
Once you get into the console, on the local client, you may receive additional information on the problem. Corrupted install, communication errors, etc.
Have you rebuilt the server?
Did you check the Sylink.xml file to make sure the clients are using the proper one to connect to the server?